The present invention relates to ramps for loading and unloading passengers or cargo between different elevations such as to an aircraft. More particularly, the invention is related to ramps, which can be used for passengers seated in wheelchairs as well as for other passengers.
It is well known to use wheeled staircases to load and unload passengers directly from an aircraft to the tarmac. This is particularly the case for smaller aircraft that are not compatible with existing boarding bridges or in airports where boarding bridges are not readily available due to high traffic or economics. For the ease of transport of passengers who are disabled, a ramp can be used in place of a staircase.
For all passengers embarking and disembarking an aircraft, it is critical that the lower end of the ramp does not extend beyond the wing tip of the plane and into the area known in the industry as the xe2x80x9cNo Goxe2x80x9d zone. The xe2x80x9cNo Goxe2x80x9d zone is so termed because encroachment of the ramp and passengers would generate a risk to themselves and to other equipment or staff.
One particular problem associated with the use of a ramp is related to the slope of the ramp and its length. The slope should be low enough to be easily traversed by foot passengers and those in wheelchairs, but the length must be such that it must not extend beyond the perimeters of a safe zone in order to achieve it.
Prior art wheeled staircases are not readily adaptable to ramps as the angle from aircraft departure door to tarmac is generally too steep. Further, merely extending the straight length of the ramp to reduce the angle does not provide a safe option as the ramp then extends beyond the safe zone. An increase in the length of a wheeled ramp also acts to decrease its maneuverability and increases its vulnerability to wind, which may result in overturning. Increasing the weight of the ramp to overcome the wind further impairs the structure""s maneuverability. Typically, wheeled units of this type have simple castors or wheels that are not easily steered, especially when attached to heavy, cumbersome apparatus.
Clearly there is a need for a passenger ramp that is maneuverable, wind-stable, easily adjusted in height, that also provides an acceptable slope and has a compact footprint so that it does not project into the xe2x80x9cNo Goxe2x80x9d zone when in use.
A mobile ramp is provided which allows for the safe loading and unloading of passengers and cargo between areas of differing elevations and where stability and a compact footprint are desired. This ramp is particularly well suited to provide passenger access to and from aircraft of varying boarding heights.
The ramp is non-linear, having at least two support frames which are pivotally connected. An arcuate planar connector acts to bridge between the ramps surface of each of the two frames while positioning them at an angle relative to one another when pivoted to an unfolded position. The compact footprint of the angled ramp is such that passengers boarding and deplaning do not enter into traffic areas of the tarmac that are unsafe, such as the xe2x80x9cNo-Goxe2x80x9d zone beyond the wing tip. Further, because of the angled orientation of the two frames, the unfolded ramp can be lengthened to maintain a low slope or gentle incline, accommodating passengers in wheelchairs, without over extending into the unsafe or xe2x80x9cNo-Goxe2x80x9d zone.
Advantageously, for transport and storage, the ramp can be folded about the pivoting connection until the first and second frames are essentially parallel, forming a more manageable unitary structure for movement about the tarmac and for alignment with an airplane passenger door. Wheels are provided at first and second ends of the first frame to permit the unit to be moved manually. A pivoting wheel is attached to a second end of the first frame adjacent the pivot to support the connected ends of the structure when folded and to provide greater maneuverability. A steerable pivoting wheel, much like an outrigger, is attached to the second frame to permit rotation of the second frame relative to the first frame between the folded and the unfolded position.
Accordingly, in a broad aspect of the invention, a mobile ramp for loading and unloading passengers from an aircraft comprises: two frames, pivotally connected for forming a contiguous ramp, a first frame having a surface forming a ramp, two wheels at an open end and a pivoting wheel at a connected end; at least a second frame having a surface forming a ramp, an open end and a connected end which is pivotally connected to the first frame""s connected end, the first and second frames being rotatable laterally about their connected ends between a folded position substantially parallel to one other and an unfolded position at an angle to one other; a bridge for extending between the connected ends of the first and second frames when in the unfolded position so that the ramps of the first and second frames become substantially contiguous at an angle to each other so that a passenger can traverse between the first and second frames respective open ends; and a pivoting wheel for supporting the second frame""s open end during rotation between the folded and unfolded positions.
In a preferred embodiment, the first frame is an upper frame and the second frame is a lower frame. Further, the elevation of the first frame""s open end is adjustable to permit vertical alignment of the mobile ramp such as with passenger doors of airplanes of varying heights.
Further, the pivoting wheel attached to the second lower frame""s open end steerable, preferably by a handle, which permits and the second lower frame between the folded and unfolded positions. More preferably the steerable wheel is further provided with a detent or other release mechanism for securing the wheel in a parallel or perpendicular orientation relative to the frames longitudinal axis, assisting in maneuvering or fixing the ramp""s position.
When the first upper and second lower frames are unfolded so that their connected ends approach, the extent of the sweep of the planar bridging extension positions the second lower ramp at an obtuse angle relative to the first frame. Preferably, the second lower ramp is positioned at an angle between substantially 95 degrees to substantially 110 degrees. Most preferably, the frame are angled at substantially 100 degrees to each other.
Preferably, an open end of the second lower ramp is supported by a castor wheel is spaced laterally and opposite the pivoting wheel to minimize flexing of the ramp under loading.